A073076 Numbers k such that 2*k+1 divides C(2*k,k).

97, 136, 178, 192, 199, 292, 313, 332, 448, 467, 472, 478, 487, 535, 542, 577, 604, 617, 697, 773, 790, 797, 852, 885, 940, 962, 967, 997, 1017, 1045, 1096, 1127, 1147, 1165, 1182, 1202, 1237, 1291, 1292, 1319, 1332, 1339, 1345, 1354, 1368, 1397, 1414

Offset: 1

Author

Benoit Cloitre, Aug 17 2002

Keywords

• easy
• nonn

Comments

Integers k such that A056617(k) = 1. - Michel Marcus, May 27 2019

Numbers n such that A005408(n) divides A000984(n). - Felix Fröhlich, May 27 2019

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000984, A005408, A056616, A056617, A080394.

Programs

Mathematica

Select[Range@ 1500, Mod[Binomial[2 #, #], 2 # + 1] == 0 &] (* Michael De Vlieger, May 27 2019 *)

PARI

isok(n) = ! (binomial(2*n, n) % (2*n+1)); \\ Michel Marcus, Nov 28 2013